Not sure what caused the led failure -- The two 6A, two 8A, and single ac line fuses are all good. Never fiddled with the fuses in the unit, though upon checking, it looks like a 10A ac line fuse was put in place of the 12A line fuse requirement set out in the specs.
Shortly before the occurrence, noticed a flash, and then a burning smell. The unit never ran hot and only got ever so slightly warm running a pair of Sound Lab ESL's, even in the heat of summer ambient temperatures with indoor temps sometimes above 90 deg. F. However, at the time of occurrence, touched the front fascia and heatsinks and it was the hottest they ever got, perhaps in the 100 deg. F range. Turned the unit off immediately, let it rest overnight.
Next morning, checked the fuses and they're all good, turned the unit on and other than the initial current inrush and dimmed lights, pure silence. Turned the tunes on and the Threshold performs without a hitch, albeit no power-on led light.
Attached are photographs of the unit. Unless i'm misinterpreting, looks like the led wires are in fact toasted, leading to that burning plastic smell.
